Inclusion Criteria:

- ≥18 years of age

- Histologically proven diagnosis of NSCLC at MSKCC Tumor positive for a translocation
or inversion event involving the ALK gene locus

- Clinical response to treatment with crizotinib as defined by either:

Radiographic partial or complete response defined by RECIST or WHO

OR:

Radiographic stable disease for at least 8 weeks

- Radiographic progression of disease amenable to biopsy while on treatment with
crizotinib as defined by RECIST or WHO

- Signed informed consent

Exclusion Criteria:

- Deemed by their treating physician to be medically unfit for biopsy

- Women who are pregnant or breast-feeding